Three-dimensional or stereoscopic video is a proven technology that is in the midst of a renaissance due to improved techniques for simultaneously delivering slightly different images, known as stereoscopic images, to a pair of offset eyes. When each of the left and right eyes view their respective portions of a stereoscopic image having a horizontal disparity, the human brain generates an illusion of depth perception from the disparity. Early stereoscopic cinema relied on different-colored filters worn over each eye to create the depth perception effect, but the overall color of the screen images appeared muted. Newer technology uses polarization filters to separate the images each eye sees. Such techniques are reaching larger audiences because of the widespread adoption of digital projectors in movie theaters, which make it easier to project stereoscopic images than did legacy equipment. With reference to FIG. 1, the mechanics of viewing a stereoscopic image are illustrated in a scene 10. Although the left and right eyes 2, 4, are focused on the same screen 6, filters 12 and 14 use filtering techniques such as those described above, or others, causes each eye to see a slightly different image. The brain then translates spatial, especially horizontal disparity of the same or similar objects in the image as the object having depth, when, in fact, both objects are projected on the same screen 6. There is accordingly a need to accurately measure disparity in stereoscopic images and to convey the measurement to a user in an informative way.
Although there are methods to measure spatial disparity of three-dimensional images, such as those described in a paper “A Taxonomy and Evaluation of Dense Two-Frame Stereo Correspondence Algorithms,” by Daniel Scharstein and Richard Szeliski, Microsoft Technical Report MSR-TR-2001-81, available at www.research.microsoft.com, which is referred to as the “Technical Report” and is incorporated by reference herein, they are typically complex and require a large amount of computing power, making them unsatisfactory to use for real-time analysis due to the large expense of processing required.
Embodiments of the invention address these and other limitations in the prior art.